Methods Inf Med 2016; 55(02): 158-165
DOI: 10.3414/ME14-01-0104
Original Articles
Schattauer GmbH

Quality Assurance of UMLS Semantic Type Assignments Using SNOMED CT Hierarchies

H. Gu
1   Computer Science Department, New York Institute of Technology, New York, NY, USA
,
Y. Chen
2   Computer Information Systems Department, BMCC, CUNY, New York, NY, USA
,
Z. He
3   Biomedical Informatics Department, Columbia University, New York, NY, USA
,
M. Halper
4   Information Technology Department, New Jersey Institute of Technology, Newark, New Jersey, USA
,
L. Chen
5   Science Department, BMCC, CUNY, New York, NY, USA
› Author Affiliations
Further Information

Publication History

received: 20 October 2014

accepted: 25 March 2015

Publication Date:
08 January 2018 (online)

Preview

Summary

Background: The Unified Medical Language System (UMLS) is one of the largest biomedical terminological systems, with over 2.5 million concepts in its Metathesaurus repository. The UMLS’s Semantic Network (SN) with its collection of 133 high-level semantic types serves as an abstraction layer on top of the Metathesaurus. In particular, the SN elaborates an aspect of the Metathesaurus’s concepts via the assignment of one or more types to each concept. Due to the scope and complexity of the Metathesaurus, errors are all but inevitable in this semantic-type assignment process.

Objectives: To develop a semi-automated methodology to help assure the quality of semantic-type assignments within the UMLS.

Methods: The methodology uses a cross- validation strategy involving SNOMED CT’s hierarchies in combination with UMLS se -mantic types. Semantically uniform, disjoint concept groups are generated programmatically by partitioning the collection of all concepts in the same SNOMED CT hierarchy according to their respective semantic-type assignments in the UMLS. Domain experts are then called upon to review the concepts in any group having a small number of concepts. It is our hypothesis that a semantic-type assignment combination applicable only to a very small number of concepts in a SNOMED CT hierarchy is an indicator of potential problems.

Results: The methodology was applied to the UMLS 2013AA release along with the SNOMED CT from January 2013. An overall error rate of 33% was found for concepts proposed by the quality-assurance methodology. Supporting our hypothesis, that number was four times higher than the error rate found in control samples.

Conclusion: The results show that the quality-assurance methodology can aid in effective and efficient identification of UMLS semantic-type assignment errors.